taxonID	type	description	language	source
03E187C8FF8ADD5FFF1D818034D33CDB.taxon	description	(Figs. 2 A – D)	en	Watters, Brian R., Nagy, Béla (2025): A review and redefinition of the subgenus Aphyobranchius Wildekamp, 1977, in the seasonal killifish genus Nothobranchius Peters, 1868 (Teleostei: Nothobranchiidae), from ephemeral wetlands of eastern Tanzania. Zootaxa 5570 (3): 401-446, DOI: 10.11646/zootaxa.5570.3.1, URL: https://doi.org/10.11646/zootaxa.5570.3.1
03E187C8FF8ADD5FFF1D818034D33CDB.taxon	materials_examined	Material examined. RMCA 77 - 16 - P- 19, holotype, male, 33.7 mm SL; – RMCA 77 - 16 - P- 20, female, 28.9 mm SL; – RMCA 77 - 16 - P- 21 - 23, 2 females, 28.2 – 28.6 mm SL; Tanzania: Ruvu drainage, Kwaraza, approx. 06 ° 41.8 ’ S, 38 ° 42 ’ E; R. Wildekamp, T. Steinfort, J. Lourens, R. van Haarlem; 12 June 1976; field code: T 76 - 8. Additional material examined. 1 male, 27.7 mm SL; Tanzania: Ruvu drainage, Kwaraza; 06 ° 40.818 ’ S, 38 ° 39.829 ’ E; B. Nagy; 12 January 2009; field code: TZN 09 - 4. – 1 male, 28.4 mm SL; Tanzania: Ruvu drainage, Soga; 06 ° 50.14 ’ S, 38 ° 50.80 ’ E; B. Watters, J. Rosenstock, M. Agnew, F. Larsen; 29 May 1998; field code: TAN 98 - 14. – 1 male, 32.6 mm SL; Tanzania: Ruvu drainage, Soga; 06 ° 50.19 ’ S, 38 ° 50.78 ’ E; B. Watters, R. Wildekamp, B. Cooper; 12 June 1997; field code: TAN 97 - 45. – 1 male, 32.0 mm SL; Tanzania: Rufiji drainage, Kitonga; 08 ° 03.110 ’ S, 39 ° 00.510 ’ E; B. Watters, B. Cooper, W. Bishopp; 29 May 2003; field code: TAN 03 - 22. – 5 males, 22.2 – 25.6 mm SL, 2 females, 21.1 – 23.5 mm SL; Tanzania: Ruhoi drainage, Ngulakula; 07 ° 48.073 ’ S, 38 ° 48.739 ’ E; B. Watters, B. Cooper, O. Schmidt; 4 June 2002; field code: TAN 02 - 13.	en	Watters, Brian R., Nagy, Béla (2025): A review and redefinition of the subgenus Aphyobranchius Wildekamp, 1977, in the seasonal killifish genus Nothobranchius Peters, 1868 (Teleostei: Nothobranchiidae), from ephemeral wetlands of eastern Tanzania. Zootaxa 5570 (3): 401-446, DOI: 10.11646/zootaxa.5570.3.1, URL: https://doi.org/10.11646/zootaxa.5570.3.1
03E187C8FF8ADD5FFF1D818034D33CDB.taxon	diagnosis	Diagnosis. Nothobranchius janpapi belongs to the N. janpapi species group within the subgenus Aphyobranchius by presenting the following combination of characters in the male: light blue body colouration with narrow red scale margins and yellow-brown to yellow-green dorsum stripe; rearward positioned dorsal fin with predorsal length of 63.3 – 67.9 % SL and predorsal length 109 – 115 as percentage of preanal length; dorsal fin relatively small with low number of rays, 12 – 14; cephalic sensory system at supraorbital level in an undivided, slightly curved, almost flat, shallow groove with three exposed neuromasts and pronounced lobes (Fig. 3 a). Both sexes with central 2 – 3 rays of the caudal fin slightly elongated forming a mild posterior lobe (vs. central lobe absent). Nothobranchius janpapi is distinguished from the other members of the N. janpapi species group by male colouration of anal fin with slender orange-red distal band and narrow light blue margin (vs. slender yellow subdistal band with narrow red distal band); caudal fin base and proximal zone olive, with light grey to translucent subdistal band and narrow dark grey distal band (vs. base and proximal zone grey to light red with slender red subdistal band and narrow black distal band in N. luekei, and caudal fin plain red to orange-red with narrow black distal margin in N. geminus); dorsal fin with narrow light-blue distal band (vs. slender red in N. luekei and narrow black in N. geminus); pelvic fin orange-red with narrow light blue distal band (vs. light blue with narrow red distal margin in N. luekei, and yellow to red with narrow black margin in N. geminus); as well as morphometric characters in males of head depth 74 – 81 % HL (vs. 66 – 72 in N. geminus and 55 – 63 in N. luekei); suborbital depth 16 – 20 % HL (vs. 10 – 14 in N. geminus and 8 – 12 in N. luekei); and caudal peduncle length 133 – 140 in % of its depth (vs. 121 – 130 in N. geminus and 148 – 156 in N. luekei). Further, it differs from N. geminus by dorsal-fin base length 18.8 – 25.1 % SL vs. 15.6 – 18.6, and from N. luekei by predorsal length 63.3 – 67.9 % SL vs. 68.0 – 73.0, and head width 58 – 65 % HL vs. 52 – 56.	en	Watters, Brian R., Nagy, Béla (2025): A review and redefinition of the subgenus Aphyobranchius Wildekamp, 1977, in the seasonal killifish genus Nothobranchius Peters, 1868 (Teleostei: Nothobranchiidae), from ephemeral wetlands of eastern Tanzania. Zootaxa 5570 (3): 401-446, DOI: 10.11646/zootaxa.5570.3.1, URL: https://doi.org/10.11646/zootaxa.5570.3.1
03E187C8FF8ADD5FFF1D818034D33CDB.taxon	description	Description. General body features illustrated by Figures 2 A – D. Morphometric and meristic characters of examined material are summarized in Table 3. Male: Small Nothobranchius species, maximum examined size 33.7 mm SL. General body shape laterally compressed. Greatest body depth at vertical in front of pelvic-fin origin (27.4 – 31.0 % SL). Greatest body width at pectoral-fin base with body progressively narrowing towards caudal-fin base. Dorsal profile slightly convex to straight from tip of snout to dorsal-fin origin, straight to slightly concave on caudal peduncle. Ventral profile convex from lower jaw to base of last anal-fin ray, straight to slightly concave on caudal peduncle. Caudal peduncle moderately deep, length 133 – 140 % of its depth. Anus situated directly in front of anal-fin origin. Head moderately long (25.6 – 30.6 % SL), laterally compressed, deeper than wide (head width 74 – 81 % of its depth). Snout distinctly pointed, smaller than eye diameter. Mouth supraterminal, slightly oblique in profile. Jaws subequal, lower jaw longer than upper, posterior end of rictus at same level or slightly ventral to centre of eye. Premaxilla and dentary with many irregularly distributed conical teeth on inner rows and slightly curved teeth on outer row. Orbit large, eye diameter 34 – 38 % HL, mainly in anterior half of head (snout to eye end length 51 – 59 % HL). Branchiostegal membrane projecting posteriorly from opercle. Dorsal-fin origin markedly posterior to anal-fin origin (predorsal length 109 – 115 as % of preanal length), both fins originating posterior to mid-length of body (predorsal length 63.3 – 67.9 % SL; preanal length 55.5 – 59.9 % SL). Dorsal fin relatively small with low number of rays, 12 – 14; extremity rounded. Anal fin trapezoidal in shape, with 16 – 19 rays; lower margin mildly concave in profile. Dorsal and anal fins usually with short fin-ray extensions. Pectoral fin subtriangular, insertion slightly posterior to margin of opercular opening, base slightly oblique, upper fin rays positioned slightly anterior to lower fin rays, with tip reaching or slightly overlapping base of pelvic fin. Pelvic fin subabdominal, origin at about mid-length of body, short, base medially separated, with tip reaching urogenital papilla. Caudal fin rounded, with 13 – 18 branched rays, plus 2 – 3 dorsal and ventral procurrent rays; central 2 – 3 rays of fin commonly relatively slightly elongated resulting in mild central lobe. Scales cycloid, body and head entirely scaled, except for ventral surface of head. No scales on base of dorsal and anal fins. Scales in mid-longitudinal series 26 – 28 plus two or three small scales on caudal-fin base. Transverse rows of scales in front of dorsal-fin origin 11; scale rows around caudal peduncle 12. Cephalic squamation pattern G-type. Frontal neuromast in single shallow groove behind upper lip. Cephalic sensory system at supraorbital level in an undivided, slightly curved, almost flat, shallow groove with three exposed neuromasts and pronounced lobes (Fig. 3 a), whereas at supratemporal level with three exposed neuromasts in slightly curved arrangement on flat surface, with pronounced lobes. Preorbital canal in shallow groove with 2 – 3 exposed neuromasts; infraorbital level with series of about 15 small buttons at ventral and posterior margin of orbit; postorbital canal in shallow groove with one exposed long neuromast. Preopercular system with six exposed neuromasts in deep groove on preopercle portion, whereas in shallow groove with four exposed neuromasts on ventral portion. Mandibular canal in shallow groove with about ten small buttons. One neuromast on each scale along trunk mid-longitudinal series. Female: Smaller than male, maximum recorded size 28.9 mm SL. Branchiostegal membrane not projecting posteriorly from opercle. Dorsal fin rounded with low number of rays, 12 – 14. Caudal fin basically rounded but with central 2 – 3 rays slightly elongated resulting in mildly pointed posterior margin. Anal fin subtriangular, tip rounded, central rays longer and more rigid. Anal fin positioned more posteriorly than in males (preanal length 60.5 – 65.2 % SL vs. 55.5 – 59.9). Anal-fin base length smaller than in males (18.7 – 20.4 % SL vs. 22.8 – 27.1). Head depth smaller than in males (67 – 69 % HL vs. 74 – 81; suborbital depth 11 – 14 % HL vs. 16 – 20), whereas head width 85 – 90 in % of its depth vs. 74 – 81. Caudal peduncle shallower than in male (caudal peduncle depth 10.7 – 11.8 % SL vs. 12.7 – 15.0; caudal peduncle length 184 – 190 % of its depth vs. 133 – 140). Colouration. Live male (Figs. 2 A – C): Scales on trunk and head light iridescent blue with narrow red to less commonly grey-brown margins, forming a regular reticulation pattern. Scales on abdomen faint blue to white with less pronounced margins. Scales on the dorsum anterior to dorsal fin may have yellow-brown centres. Snout, frontal and dorsal portions of the head are yellow-brown; the throat is yellow. Operculum has light blue markings. Exposed part of branchiostegal membrane is yellow with white edging. Iris is blue to blue-green. Dorsal fin background is green to yellow-green grading to grey in the distal zone with a light blue margin that may be white in the very short fin-ray extensions; the background is overlaid by small red spots that may be denser and larger in the basal and proximal zones, becoming smaller and, in some populations, dark grey in the medial and distal zones. Anal fin background comprises a light blue basal zone grading to yellow-brown or yellow-green in the proximal and medial zones which are overlaid by prominent red stripes over fin rays; in some populations these red stripes may be partially broken into irregular spots. The development of red stripes is variable at both the inter- and intrapopulation level; in some they are narrow, allowing the yellow-brown or yellow-green background to dominate, while in others they are broad and dense resulting in an almost solid red fin and merging with the commonly present orange-red distal zone. A narrow, often only partially developed, light blue margin is usually present on the anal fin. Basal, proximal and medial zones of the caudal fin are olive grading into a light grey to translucent subdistal zone that, in turn, grades into a darker grey outer component. Faint red spots may be present on the basal, proximal and submedial zones and may be arranged concentrically conforming to the general outer shape of the fin; less commonly, there may be radiating red stripes parallel to fin rays. Many populations also show orange-red markings along the lower, and more rarely upper, marginal parts of the distal zone of the caudal fin, extending from the fin base and decreasing anteriorly. Pelvic fins are orange-red with poorly developed blue-white edges. Pectoral fins are dominantly hyaline with poorly developed, and usually only partial, blue margins. Live female (Fig. 2 D): Trunk and head light grey, darker on the dorsum and lighter ventrally. Scales on the flanks have narrow darker grey-brown margins; scale centres on the trunk above the abdomen are iridescent pale blue; the operculum is iridescent light blue. All fins hyaline. The iris is light golden.	en	Watters, Brian R., Nagy, Béla (2025): A review and redefinition of the subgenus Aphyobranchius Wildekamp, 1977, in the seasonal killifish genus Nothobranchius Peters, 1868 (Teleostei: Nothobranchiidae), from ephemeral wetlands of eastern Tanzania. Zootaxa 5570 (3): 401-446, DOI: 10.11646/zootaxa.5570.3.1, URL: https://doi.org/10.11646/zootaxa.5570.3.1
03E187C8FF8ADD5FFF1D818034D33CDB.taxon	distribution	Distribution. Nothobranchius janpapi is endemic to seasonal freshwater habitats in coastal Tanzania and is the most common, but second most widespread, member of the Aphyobranchius subgenus, occurring mainly in the Ruvu and Rufiji river systems (Fig. 1). It occurs in the middle and lower reaches of the latter and throughout most of the former but dominantly in the lower reaches. The westernmost locality known to date is in the Kisaki area on the floodplain of the Mgeta River, a tributary of the upper Ruvu River system. There is currently a lack of range data available for the middle reaches of the Ruvu River, but this can probably be attributed to a lack of investigation in that area. The northern extent of distribution is in the southern part of the Wami River delta where it merges with the coastal plains associated with the Ruvu River. The southernmost occurrences are in the coastal floodplains immediately south of the Rufiji delta, probably extending to the lower Matandu River system where a population of what has provisionally been referred to as “ N. cf. janpapi ” is present. The affiliation of this southern population is presently being studied. A single, relatively isolated, occurrence is also known from the Luhule / Luhute River floodplain within the so-called Mbezi Triangle (sensu Watters et al. 2007; Watters 2009). Conservation status. Nothobranchius janpapi has been evaluated as Least Concern (Nagy & Watters 2019 a). The known extent of occurrence (EOO) is 22,790 km ². Within its area of distribution, the occurrence of the species is fragmented but it seems to be relatively widespread, and it is known from more than 30 threat-based locations in several river drainages. These factors make it the least threatened member of the Aphyobranchius subgenus. However, there is increasing habitat degradation due to expansion of agriculture and urbanisation across its range, including the conversion of some seasonal habitats into permanent ponds (e. g. in the Kwaraza area of the lower Ruvu River system, where the type locality occurs), thereby modifying them in ways that render them unsuitable to support the semi-annual life cycle of the species.	en	Watters, Brian R., Nagy, Béla (2025): A review and redefinition of the subgenus Aphyobranchius Wildekamp, 1977, in the seasonal killifish genus Nothobranchius Peters, 1868 (Teleostei: Nothobranchiidae), from ephemeral wetlands of eastern Tanzania. Zootaxa 5570 (3): 401-446, DOI: 10.11646/zootaxa.5570.3.1, URL: https://doi.org/10.11646/zootaxa.5570.3.1
03E187C8FF86DD5BFF1D86B7356E3FDF.taxon	description	(Figs. 4 A – C)	en	Watters, Brian R., Nagy, Béla (2025): A review and redefinition of the subgenus Aphyobranchius Wildekamp, 1977, in the seasonal killifish genus Nothobranchius Peters, 1868 (Teleostei: Nothobranchiidae), from ephemeral wetlands of eastern Tanzania. Zootaxa 5570 (3): 401-446, DOI: 10.11646/zootaxa.5570.3.1, URL: https://doi.org/10.11646/zootaxa.5570.3.1
03E187C8FF86DD5BFF1D86B7356E3FDF.taxon	materials_examined	Material examined. 5 males, 21.2 – 22.9 mm SL, 1 female, 21.3 mm SL; Tanzania: Mbezi drainage, Mkuranga; 07 ° 11.615 ’ S, 39 ° 10.289 ’ E; B. Watters, B. Cooper, O. Schmidt; 16 June 2000; field code: TAN 00 - 23; – 2 males, 25.4 – 26.2 mm SL, 1 female, 24.6 mm SL; Tanzania: Mbezi drainage, Mkuranga; 07 ° 11.617 ’ S, 39 ° 10.299 ’ E; B. Nagy; 13 January 2009; field code: TZN 09 - 9.	en	Watters, Brian R., Nagy, Béla (2025): A review and redefinition of the subgenus Aphyobranchius Wildekamp, 1977, in the seasonal killifish genus Nothobranchius Peters, 1868 (Teleostei: Nothobranchiidae), from ephemeral wetlands of eastern Tanzania. Zootaxa 5570 (3): 401-446, DOI: 10.11646/zootaxa.5570.3.1, URL: https://doi.org/10.11646/zootaxa.5570.3.1
03E187C8FF86DD5BFF1D86B7356E3FDF.taxon	diagnosis	Diagnosis. Nothobranchius luekei belongs to the N. janpapi species group within the subgenus Aphyobranchius by presenting the following combination of characters in the male: light blue body colouration with narrow red scale margins and yellow-brown to yellow-green dorsum stripe; rearward positioned dorsal fin with predorsal length of 68 – 73.0 % SL and predorsal length 117 – 122 as % of preanal length; dorsal fin relatively small with low number of rays, 11 – 13; cephalic sensory system at supraorbital level in an undivided, slightly curved, almost flat, shallow groove with three exposed neuromasts and pronounced lobes (Fig. 3 b). Both sexes with central 2 – 3 rays of the caudal fin slightly elongated forming a posterior lobe (vs. central lobe absent). Nothobranchius luekei is distinguished from the other members of the N. janpapi species group by male colouration of anal fin with slender yellow subdistal band and narrow red margin (vs. slender orange-red distal band with narrow light blue margin in N. janpapi); caudal fin base and proximal zone grey to light red with slender red subdistal band and narrow black distal band (vs. base and proximal zone olive, and with light grey to translucent subdistal band and narrow dark grey distal band in N. janpapi, and plain red to orange-red with narrow black distal margin in N. geminus); pelvic fin light blue with yellow subdistal band and narrow red distal band (vs. plain orange-red with narrow light blue distal band in N. janpapi, and yellow to red with narrow black distal band in N. geminus); as well as morphometric characters in males of body depth at pelvic-fin origin 21.5 – 23.6 % SL (vs. 25.3 – 30.2 in N. geminus and 27.4 – 31.0 in N. janpapi); head depth 55 – 63 % HL (vs. 66 – 72 in N. geminus and 74 – 81 in N. janpapi); head width 87 – 97 as % of its depth (vs. 73 – 83 in N. geminus and 74 – 81 in N. janpapi); and caudal peduncle length 148 – 156 as % of its depth (vs. 121 – 130 in N. geminus and 133 – 140 in N. janpapi). Further, it differs from N. janpapi by predorsal length 68.0 – 73.0 % SL (vs. 63.3 – 67.9 % SL); head width 52 – 56 % HL (vs. 58 – 65 %); and suborbital depth 8 – 12 % HL (vs. 16 – 20).	en	Watters, Brian R., Nagy, Béla (2025): A review and redefinition of the subgenus Aphyobranchius Wildekamp, 1977, in the seasonal killifish genus Nothobranchius Peters, 1868 (Teleostei: Nothobranchiidae), from ephemeral wetlands of eastern Tanzania. Zootaxa 5570 (3): 401-446, DOI: 10.11646/zootaxa.5570.3.1, URL: https://doi.org/10.11646/zootaxa.5570.3.1
03E187C8FF86DD5BFF1D86B7356E3FDF.taxon	description	Description. General body features illustrated by Figures 4 A – C. Morphometric and meristic characters of examined material summarized in Table 4. Male: Small Nothobranchius species, maximum size of examined specimens 26.2 mm SL. General body shape laterally compressed. Greatest body depth at vertical in front of pelvic-fin origin (21.5 – 23.6 % SL). Greatest body width at pectoral-fin base with body progressively narrowing towards caudal-fin base. Dorsal profile straight from tip of snout to dorsal-fin origin, slightly concave on caudal peduncle. Ventral profile convex from lower jaw to base of last anal-fin ray, straight to slightly concave on caudal peduncle. Caudal peduncle deep, length 148 – 156 % of its depth. Anus situated directly in front of anal-fin origin. Head moderately long (27.1 – 31.1 % SL), laterally compressed, slightly deeper than wide (head width 87 – 97 % of its depth). Snout distinctly pointed, smaller than eye diameter. Mouth supraterminal, slightly oblique in profile. Jaws subequal, lower jaw longer than upper, posterior end of rictus at same level or slightly ventral to centre of eye. Premaxilla and dentary with many irregularly distributed conical teeth on inner rows and slightly curved teeth on outer row. Orbit large, eye diameter 32 – 37 % HL, mainly in anterior half of head (snout to eye end length 52 – 58 % HL). Branchiostegal membrane projecting posteriorly from opercle. Dorsal-fin origin markedly posterior to anal-fin origin (predorsal length 117 – 122 as % of preanal length), both fins originating posterior to mid-length of body (predorsal length 68.0 – 73.0 % SL; preanal length 55.7 – 60.5 % SL). Dorsal fin relatively small with low number of rays, 11 – 13; extremity rounded. Anal fin trapezoidal in shape, with 17 – 19 rays; lower margin quite strongly concave in profile, resulting in mildly lobate rear part of fin. Dorsal and anal fins with short fin-ray extensions. Pectoral fin subtriangular, insertion slightly posterior to margin of opercular opening, base slightly oblique, upper fin rays positioned slightly anterior to lower fin rays, with tip reaching or slightly overlapping base of pelvic fin. Pelvic fin subabdominal, origin at about mid-length of body, short, base medially separated, with tip reaching urogenital papilla. Caudal fin rounded, with 13 – 16 branched rays, plus 3 – 4 dorsal and ventral procurrent rays; central 2 – 3 rays of fin relatively slightly elongated resulting in mild central lobe. Scales cycloid, body and head entirely scaled, except for ventral surface of head. No scales on base of dorsal and anal fins. Scales in mid-longitudinal series 26 – 28 plus 2 – 3 small scales on caudal-fin base. Transverse rows of scales in front of dorsal-fin origin 10; scale rows around caudal peduncle 12. Cephalic squamation pattern G-type. Frontal neuromast in single shallow groove behind upper lip. Cephalic sensory system at supraorbital level in an undivided, slightly curved zigzag pattern, almost flat, shallow groove with three exposed neuromasts and pronounced lobes (Fig. 3 b), whereas at supratemporal level with three exposed neuromasts in slightly curved arrangement on flat surface, with pronounced lobes. Preorbital canal in deep groove with two exposed neuromasts; infraorbital level with series of about 20 small buttons at ventral and posterior margin of orbit; postorbital canal in deep groove with one exposed neuromast. Preopercular system with six exposed neuromasts in deep groove on preopercle portion, whereas in shallow groove with six small neuromasts on ventral portion. Mandibular canal in shallow groove with about 20 small buttons. One neuromast on each scale along trunk mid-longitudinal series. Female: Smaller than male, maximum recorded size 24.6 mm SL. Branchiostegal membrane not projecting posteriorly from opercle. Dorsal fin rounded with low number of fin rays, 11 – 12. Caudal fin basically rounded but with central 2 – 3 rays elongated resulting in pointed posterior margin. Anal fin subtriangular, tip rounded, central rays longer and more rigid; posterior lower margin may be very slightly concave, mimicking in very mild way, that of male. Anal-fin base length smaller than in male (19.7 – 20.3 % SL vs. 21.9 – 26.3). Caudal peduncle shallower than in males (caudal peduncle length 161 – 167 % of its depth vs. 148 – 156). Colouration. Live male (Figs. 4 A – B): Scales on the trunk and head are light iridescent blue to blue-green with red margins, forming a regular reticulation pattern. Scales on the abdomen are faint blue to cream with less pronounced margins. Scales on the dorsum anterior to the dorsal fin have yellow-green centres forming a narrow stripe. Snout, and frontal and dorsal portions of head, are yellow-green (Mbezi population) or grey (Luhule / Luhute population); the throat is yellow-green. Operculum has blue to blue-green, and lesser red, markings with intervening yellow areas. Exposed part of the branchiostegal membrane is yellow with white edging. Iris is blue to blue-green. Dorsal fin background light blue-green in the basal and proximal zones grading to yellow through the medial zone and into the distal zone; background overlaid by irregular red spots and patches that become coarser in the medial and distal zones (Luhule / Luhute) that may also take the form of streaks parallel to fin rays (Mbezi), merging in the distal zone as an irregular marginal band. Anal fin background comprises light blue basal and proximal zones grading to blue-green through the medial zone to yellow in the subdistal zone. In the Luhule / Luhute population the anal fin background is overlaid by narrow irregular red bands over the proximal, sub-medial, medial and distal zones, the latter forming a distinct marginal band; in the Mbezi population the background is overlaid by prominent red streaks arranged parallel to fin rays that end at the yellow subdistal zone and there is a red marginal band in the distal zone. Basal, proximal and medial zones of the caudal fin are grey (Luhule / Luhute) or light red (Mbezi), with red spots and streaks, the latter aligned parallel to the fin rays; in the Luhule / Luhute population the distal zone comprises a broad red band followed by a black marginal band; in the Mbezi population the distal zone grades from a relatively dark red outwards to a lighter red, with no black margin. Pelvic fins mimic, in part, the pattern of anal fin with light blue overlaid by red markings, followed by an irregular red band or red spots, a yellow band and red edging. Pectoral fins are dominantly hyaline or pale yellow with prominent blue margins. Live female (Fig. 4 C): Trunk and head are light grey, darker on the dorsum and lighter ventrally. Scales have narrow darker grey margins on the flanks, becoming broader on the back; scale centres on the trunk above the abdomen are iridescent pale blue; the operculum is iridescent blue-green. All fins are hyaline. The iris is golden.	en	Watters, Brian R., Nagy, Béla (2025): A review and redefinition of the subgenus Aphyobranchius Wildekamp, 1977, in the seasonal killifish genus Nothobranchius Peters, 1868 (Teleostei: Nothobranchiidae), from ephemeral wetlands of eastern Tanzania. Zootaxa 5570 (3): 401-446, DOI: 10.11646/zootaxa.5570.3.1, URL: https://doi.org/10.11646/zootaxa.5570.3.1
03E187C8FF86DD5BFF1D86B7356E3FDF.taxon	distribution	Distribution. Nothobranchius luekei is endemic to seasonal freshwater habitats in coastal Tanzania and is relatively sparsely distributed over a restricted range. Confirmed sites occur in association with the Mbezi and Luhule / Luhute river systems in the near coastal region south of Dar es Salaam. It appears to be confined to the so-called Mbezi Triangle (sensu Watters et al. 2007; Watters 2009), a region that is separated to varying degrees from the Ruvu and Rufiji systems by the Pugu and Mtoti hills, respectively (Fig. 1). Conservation status. Nothobranchius luekei has been assessed as Endangered B 1 ab (iii) + 2 ab (iii) (Nagy & Watters 2019 b). The known extent of occurrence (EOO) is 238 km ², with a maximum estimate of around 1,000 km ², whereas the area of occupancy (AOO) is 24 km ², with a maximum estimate of around 100 km ². Within its restricted area of distribution, the occurrence of the species is fragmented and currently it is known from only five threat-based locations. As observed directly by the authors during the course of repeated visits to localities over a number of years, there is increasing pressure on land resources due to the expansion of agriculture in both principal areas where this species occurs. Such expansion of agricultural activity is resulting in habitat degradation and modification, rendering them unsuitable to support the semi-annual life cycle of the species and by altering conditions of the habitat niche preferred by this species. This category is assigned based on using the upper estimates of the EOO, AOO, and number of locations as best estimates. As presently known, this species is restricted to the Mbezi Triangle (sensu Watters et al. 2007; Watters 2009) in coastal Tanzania, and its distribution will remain restricted by geographic confinement and configuration of the drainage systems.	en	Watters, Brian R., Nagy, Béla (2025): A review and redefinition of the subgenus Aphyobranchius Wildekamp, 1977, in the seasonal killifish genus Nothobranchius Peters, 1868 (Teleostei: Nothobranchiidae), from ephemeral wetlands of eastern Tanzania. Zootaxa 5570 (3): 401-446, DOI: 10.11646/zootaxa.5570.3.1, URL: https://doi.org/10.11646/zootaxa.5570.3.1
03E187C8FF82DD44FF1D828433FD385F.taxon	description	(Figs. 5 A – B)	en	Watters, Brian R., Nagy, Béla (2025): A review and redefinition of the subgenus Aphyobranchius Wildekamp, 1977, in the seasonal killifish genus Nothobranchius Peters, 1868 (Teleostei: Nothobranchiidae), from ephemeral wetlands of eastern Tanzania. Zootaxa 5570 (3): 401-446, DOI: 10.11646/zootaxa.5570.3.1, URL: https://doi.org/10.11646/zootaxa.5570.3.1
03E187C8FF82DD44FF1D828433FD385F.taxon	materials_examined	Material examined. RMCA 97 - 83 - P- 1, holotype, male, 32.3 mm SL; – RMCA 97 - 83 - P- 2 - 17, paratypes, 9 males 28.3 – 32.3 mm SL, 7 females, 25.8 – 30.2 mm SL; Tanzania: Kilombero drainage, Ifakara; 08 ° 10.042 ’ S, 36 ° 41.611 ’ E; B. Watters, R. Wildekamp, I. Sainthouse; 7 June, 1995; field code: TAN 95 - 4. Additional material examined. 1 male, 28.1 mm SL; Tanzania: Kilombero drainage, Narubungo; 08 ° 08.882 ’ S, 36 ° 24.911 ’ E; B. Watters, B. Cooper, O. Schmidt; 9 June 2002; field code: TAN 02 - 24. – 1 male, 30.1 mm SL; Tanzania: Kilombero drainage, Iragua; 08 ° 33.175 ’ S, 36 ° 30.245 ’ E; B. Watters, B. Cooper, O. Schmidt; 12 June 2000; field code: TAN 00 - 16.	en	Watters, Brian R., Nagy, Béla (2025): A review and redefinition of the subgenus Aphyobranchius Wildekamp, 1977, in the seasonal killifish genus Nothobranchius Peters, 1868 (Teleostei: Nothobranchiidae), from ephemeral wetlands of eastern Tanzania. Zootaxa 5570 (3): 401-446, DOI: 10.11646/zootaxa.5570.3.1, URL: https://doi.org/10.11646/zootaxa.5570.3.1
03E187C8FF82DD44FF1D828433FD385F.taxon	diagnosis	Diagnosis. Nothobranchius geminus belongs to the N. janpapi species group within the subgenus Aphyobranchius by presenting the following combination of characters in the male: light blue body colouration with narrow red scale margins and yellow-brown to yellow-green dorsum stripe; rearward positioned dorsal fin with predorsal length of 61.2 – 70.8 % SL and predorsal length 112 – 125 in % of preanal length; dorsal fin relatively small with low number of rays, 11 – 13; cephalic sensory system at supraorbital level in an undivided, slightly curved, almost flat, shallow groove with three exposed neuromasts and pronounced lobes (Fig 3 c). Both sexes with central 2 – 3 rays of the caudal fin elongated forming a posterior lobe (vs. central lobe absent). Nothobranchius geminus is distinguished from the other members of the N. janpapi species group by male colouration of anal fin with slender pale yellow subdistal band and narrow red margin (vs. slender orange-red distal band with narrow light blue margin in N. janpapi); caudal fin plain red to orange-red with narrow black distal margin (vs. base and proximal zone olive, and with light grey to translucent subdistal band and narrow dark grey distal band in N. janpapi, and base and proximal zone grey to light red with red subdistal band and narrow black distal band in N. luekei); pelvic fin yellow to red with narrow black margin (vs. plain orange-red with narrow light blue distal band in N. janpapi, and light blue with narrow red distal margin in N. luekei); by morphometric characters of head depth 66 – 72 % HL (vs. 74 – 81 in N. janpapi, and 55 – 63 in N. luekei) and caudal peduncle length 121 – 130 as % of its depth (vs. 133 – 140 in N. janpapi, and 148 – 156 in N. luekei); and, it differs from N. janpapi by dorsal-fin base length 15.6 – 18.6 % SL (vs. 18.8 – 25.1). Further, the female differs in the colouration element of small, sparsely distributed red-brown spots across mid- to upper parts of flanks and head (vs. absent in N. janpapi and N. luekei)	en	Watters, Brian R., Nagy, Béla (2025): A review and redefinition of the subgenus Aphyobranchius Wildekamp, 1977, in the seasonal killifish genus Nothobranchius Peters, 1868 (Teleostei: Nothobranchiidae), from ephemeral wetlands of eastern Tanzania. Zootaxa 5570 (3): 401-446, DOI: 10.11646/zootaxa.5570.3.1, URL: https://doi.org/10.11646/zootaxa.5570.3.1
03E187C8FF82DD44FF1D828433FD385F.taxon	description	Description. General body features illustrated by Figures 5 A – B. Morphometric and meristic characters of examined material are summarized in Table 5. Male: Small Nothobranchius species, maximum recorded size 32.3 mm SL. General body shape laterally compressed. Greatest body depth at vertical in front of pelvic-fin origin (25.3 – 30.2 % SL). Greatest body width at pectoral-fin base with body progressively narrowing towards caudal-fin base. Dorsal profile slightly concave from tip of snout to nape and straight to slightly convex from nape to dorsal-fin origin, straight to slightly concave on caudal peduncle. Ventral profile convex from lower jaw to base of last anal-fin ray, straight to slightly concave on caudal peduncle. Caudal peduncle moderately deep, length 121 – 130 % of its depth. Anus situated directly in front of anal-fin origin. Head moderately long (27.9 – 32.4 % SL), laterally compressed, deeper than wide (head width 73 – 83 % of its depth). Snout distinctly pointed, smaller than eye diameter. Mouth supraterminal, slightly oblique in profile. Jaws subequal, lower jaw longer than upper, posterior end of rictus at same level or slightly ventral to centre of eye. Premaxilla and dentary with many irregularly distributed conical teeth on inner rows and slightly curved teeth on outer row. Orbit large, eye diameter 28 – 34 % HL, mainly in anterior half of head (snout to eye end length 49 – 58 % HL). Branchiostegal membrane projecting posteriorly from opercle. Dorsal-fin origin markedly posterior to anal-fin origin (predorsal length 112 – 125 as % of preanal length), both fins originating posterior to mid-length of body (predorsal length 61.2 – 70.8 % SL; preanal length 52.5 – 59.8 % SL). Dorsal fin relatively small with low number of rays, 11 – 13; extremity rounded. Anal fin trapezoidal in shape, with 17 – 21 rays; lower margin moderately concave in profile. Dorsal and anal fins with short fin-ray extensions. Pectoral fin subtriangular, insertion slightly posterior to margin of opercular opening, base slightly oblique, upper fin rays positioned slightly anterior to lower fin rays, with tip reaching or slightly overlapping base of pelvic fin. Pelvic fin subabdominal, origin at about mid-length of body, short, base medially separated, with tip reaching urogenital papilla. Caudal fin rounded, with 13 – 16 branched rays, plus 3 – 4 dorsal and ventral procurrent rays; central 2 – 3 rays of fin relatively slightly elongated resulting in mild central lobe. Scales cycloid, body and head entirely scaled, except for ventral surface of head. No scales on base of dorsal and anal fins. Scales in mid-longitudinal series 26 – 28 plus 2 – 3 small scales on caudal-fin base. Transverse rows of scales in front of dorsal-fin origin 11; scale rows around caudal peduncle 12. Cephalic squamation pattern G-type. Frontal neuromast in single shallow groove behind upper lip. Cephalic sensory system at supraorbital level in an undivided, slightly curved zigzag pattern, almost flat shallow groove with three exposed neuromasts and pronounced lobes (Fig. 3 c), whereas at supratemporal level with three exposed neuromasts in undivided, slightly curved shallow groove. Preorbital canal in shallow groove with two exposed neuromasts; infraorbital level with series of about 20 small buttons at ventral and posterior margin of orbit; postorbital canal in deep groove with one exposed neuromast. Preopercular system with six exposed neuromasts in deep groove on preopercle portion, whereas in shallow groove with about ten small buttons on ventral portion. Mandibular canal in shallow groove with about six small neuromasts. One neuromast on each scale along trunk mid-longitudinal series. Female: Smaller than male, maximum recorded size 30.2 mm SL. Branchiostegal membrane not projecting posteriorly from opercle. Dorsal fin rounded with low number of fin rays, 11 – 13. Caudal fin basically rounded but with central 2 – 3 rays slightly elongated resulting in pointed posterior margin. Anal fin subtriangular, tip rounded, central rays longer and more rigid. Anal-fin base length smaller than in males (17.9 – 21.3 % SL vs. 25.6 – 28.3). Head depth smaller than in males (58 – 65 % HL vs. 66 – 72). Caudal peduncle shallower than in males (caudal peduncle length 157 – 164 % of its depth vs. 121 – 130). Colouration. Live male (Fig. 5 A): Scales on the trunk and head light iridescent blue to blue-green with prominent red margins, forming a regular reticulation pattern. Scales on the abdomen are faint blue to cream with less pronounced margins. Scales on the dorsum anterior to the dorsal fin have yellow-brown centres forming a narrow zone. Snout, frontal and dorsal portions of the head and throat are yellow. Operculum yellow with sparse blue to blue-green and red markings. Exposed part of the branchiostegal membrane is yellow with white edging. Iris golden yellow to golden blue-green, reflective pale blue when viewed from above. Dorsal fin light blue-green in the basal and proximal zones grading to yellow-green through the medial zone and into the distal zone, overlaid by irregular red spots and streaks in crude parallelism with fin rays in the proximal and submedial zones but arranged somewhat concentrically conforming to the fin margin in the medial and posterior zones; the distal zone comprises a solid red band that may be followed by a very narrow black margin. Short extensions to the dorsal and anal fins are black where the similarly coloured margin is present but are otherwise red. Anal fin background colour is light blue in the basal zone and light blue or yellow in the proximal zone grading to yellow through the medial and subdistal zones; the proximal and medial zones are overlaid by red spots that commonly merge to form stripes aligned parallel to the fin rays. The density of these red markings is variable at both the inter-and intrapopulation levels to the extent that they may be present in the proximal zone but grade outwards to absent in the medial zone. There is always a narrow red margin to the anal fin and short fin-ray extensions may be red or black as discussed above. The caudal fin is red to orange-red with a narrow dark grey to black margin most prominent anteriorly; fin rays may be a darker red than the intervening membrane. Pelvic fins are yellow to light blue with a variable density of red spots, and a red marginal zone that may also show incomplete black edging. Pectoral fins are dominantly hyaline or pale yellow with narrow and irregular blue margins. Live female (Fig. 5 B): The trunk and head are overall light grey with light blue to blue-green iridescence on the scales which have pale grey edgings; small red-brown spots are sparsely distributed across the mid- to upper parts of the flanks and head, being more common over the upper body. The operculum is iridescent very pale blue-green. All fins are hyaline. The iris is golden.	en	Watters, Brian R., Nagy, Béla (2025): A review and redefinition of the subgenus Aphyobranchius Wildekamp, 1977, in the seasonal killifish genus Nothobranchius Peters, 1868 (Teleostei: Nothobranchiidae), from ephemeral wetlands of eastern Tanzania. Zootaxa 5570 (3): 401-446, DOI: 10.11646/zootaxa.5570.3.1, URL: https://doi.org/10.11646/zootaxa.5570.3.1
03E187C8FF82DD44FF1D828433FD385F.taxon	distribution	Distribution. Nothobranchius geminus is endemic to seasonal freshwater habitats in central-eastern Tanzania and has been found in the seasonal marginal and peripheral zones of the Kibasira Swamp in the Kilombero River valley. The latter system represents a fairly remote component of the Rufiji River system, connected to it through the Ulanga River, the downstream continuation of the Kilombero River. Known sites are associated with the northeastern part of the Swamp, south-southwest and west-southwest of the town of Ifakara (Watters 2016 b). However, the Kibasira Swamp is a vast entity and undoubtedly the distribution of this species is significantly greater than has presently been reported and is expected to also extend throughout the less accessible southwestern part of the Swamp that is yet to be fully investigated (Fig. 1). Conservation status. Nothobranchius geminus is listed as Vulnerable B 1 ab (iii) (Nagy & Watters 2019 c). The known extent of occurrence (EOO) is 978 km ², with a maximum estimate of around 6,000 km ². Within its restricted area of distribution, the occurrence of the species is fragmented and currently it is known from only five threat-based locations. However, it is expected to occur at up to 10 threat-based locations within the drainage of the Kilombero River. This species is expected to also inhabit the southwestern parts of the Kibasira Swamp that are yet to be fully investigated; all presently known sites are in the northeastern parts of the swamp. In combination with its annual life cycle in seasonal habitats, its dependence on the clay-rich vertisol-type substratum for embryonic development makes it more subject to threats, as is the case with all other members of the subgenus. This category is assigned based on the upper estimates of the EOO and number of threat-based locations as best estimates. Notably, drainage modifications associated with road construction has resulted in the destruction of the type locality for this species.	en	Watters, Brian R., Nagy, Béla (2025): A review and redefinition of the subgenus Aphyobranchius Wildekamp, 1977, in the seasonal killifish genus Nothobranchius Peters, 1868 (Teleostei: Nothobranchiidae), from ephemeral wetlands of eastern Tanzania. Zootaxa 5570 (3): 401-446, DOI: 10.11646/zootaxa.5570.3.1, URL: https://doi.org/10.11646/zootaxa.5570.3.1
03E187C8FF9DDD40FF1D850434623DBB.taxon	description	(Figs. 6 A – D)	en	Watters, Brian R., Nagy, Béla (2025): A review and redefinition of the subgenus Aphyobranchius Wildekamp, 1977, in the seasonal killifish genus Nothobranchius Peters, 1868 (Teleostei: Nothobranchiidae), from ephemeral wetlands of eastern Tanzania. Zootaxa 5570 (3): 401-446, DOI: 10.11646/zootaxa.5570.3.1, URL: https://doi.org/10.11646/zootaxa.5570.3.1
03E187C8FF9DDD40FF1D850434623DBB.taxon	materials_examined	Material examined. RMCA 77 - 16 - P- 28, holotype, male, 40.6 mm SL; – RMCA 77 - 16 - P- 29 - 33, 5 males, 39.3 mm SL, 4 females, 30.4 – 35.4 mm SL; Tanzania: Kwaraza village; approx. 06 ° 41.9 ’ S, 38 ° 42.3 ’ E; R. Wildekamp, T. Steinfort, R. van Haarlem; 12 June 1976; field code: T 76 - 8. Additional material examined. 3 males, 32.5 – 35.6 mm SL; Tanzania: Kilombero drainage, Ifakara; 08 ° 10.042 ’ S, 36 ° 41.611 ’ E; B. Watters, R. Wildekamp, I. Sainthouse; 7 June 1995; field code: TAN 95 - 4.	en	Watters, Brian R., Nagy, Béla (2025): A review and redefinition of the subgenus Aphyobranchius Wildekamp, 1977, in the seasonal killifish genus Nothobranchius Peters, 1868 (Teleostei: Nothobranchiidae), from ephemeral wetlands of eastern Tanzania. Zootaxa 5570 (3): 401-446, DOI: 10.11646/zootaxa.5570.3.1, URL: https://doi.org/10.11646/zootaxa.5570.3.1
03E187C8FF9DDD40FF1D850434623DBB.taxon	diagnosis	Diagnosis. Nothobranchius lourensi is distinguished from all the other members of the genus Nothobranchius by the unique combination of diagnostic characters of male colouration comprising: blue-green scales with dark brown posterior scale margins, creating a reticulation on the body, with a chevron pattern on the posterior part of trunk; light blue throat; anal and caudal fins with 8 – 12 distinct narrow to slender bands on the entire fin, perpendicular to fin rays, alternating red-brown and light blue to light yellow, with iridescent light blue to yellow subdistal band and dark grey to black distal band; dorsal-fin anterior half with irregular red brown spots and stripes parallel to fin rays, whereas posterior half with alternating red-brown and light blue to light yellow narrow to slender bands, perpendicular to fin rays; as well as having an anal fin with posterior lower margin straight to mildly concave. Also, the female has a grey-brown body, with a dark grey chevron pattern on the posterior half of trunk.	en	Watters, Brian R., Nagy, Béla (2025): A review and redefinition of the subgenus Aphyobranchius Wildekamp, 1977, in the seasonal killifish genus Nothobranchius Peters, 1868 (Teleostei: Nothobranchiidae), from ephemeral wetlands of eastern Tanzania. Zootaxa 5570 (3): 401-446, DOI: 10.11646/zootaxa.5570.3.1, URL: https://doi.org/10.11646/zootaxa.5570.3.1
03E187C8FF9DDD40FF1D850434623DBB.taxon	description	Description. General body features illustrated by Figures 6 A – D. Morphometric and meristic characters of examined material are summarized in Table 6. Male: Medium-sized Nothobranchius species, maximum recorded size 40.6 mm SL. General body shape robust, laterally compressed and deep. Greatest body depth at pelvic-fin origin, 28.6 – 34.0 % SL. Greatest body width at pectoral-fin base with body progressively narrowing towards caudal-fin base. Dorsal profile convex from tip of snout to dorsal-fin origin, straight to slightly concave on caudal peduncle. Ventral profile convex from lower jaw to base of last anal-fin ray, straight to slightly concave on caudal peduncle. Caudal peduncle deep, length 144 – 152 % of its depth. Anus situated directly in front of anal-fin origin. Head moderately long (29.2 – 32.8 % SL), laterally compressed, deeper than wide (head width 64 – 70 % of its depth). Snout distinctly pointed, smaller than eye diameter. Mouth supraterminal, slightly oblique in profile. Jaws subequal, lower jaw longer than upper, posterior end of rictus at same level or slightly ventral to centre of eye. Premaxilla and dentary with many irregularly distributed conical teeth on inner rows and slightly curved teeth on outer row. Orbit moderately large, eye diameter 27 – 36 % HL, positioned entirely in anterior half of head (snout to eye end length 45 – 50 % HL). Branchiostegal membrane projecting posteriorly from opercle. Dorsal-fin origin at about same vertical positioning as anal-fin origin (mean predorsal length 94 – 105 as % of preanal length), both fins originating slightly posterior to mid-length of body (predorsal length 52.3 – 56.2 % SL; preanal length 53.7 – 57.6 % SL). Dorsal fin with 14 – 16 rays, extremity rounded. Anal fin anterior margin and anterior part of lower margin rounded, posterior part of lower margin straight to mildly concave, angular to posterior margin, with 17 – 20 rays. Dorsal and anal fins with short fin-ray extensions. Pectoral fin subtriangular, insertion slightly posterior to margin of opercular opening, base slightly oblique, upper fin rays positioned slightly anterior to lower fin rays, with tip reaching or slightly overlapping base of pelvic fin. Pelvic fin subabdominal, origin at about mid-length of body, short, base medially separated, with tip reaching urogenital papilla. Caudal fin rounded, with 14 – 18 branched rays, plus 3 – 4 dorsal and ventral procurrent rays. Scales cycloid, body and head entirely scaled, except for ventral surface of head. No scales on base of dorsal and anal fins. Scales in mid-longitudinal series 28 – 30 plus two or three small scales on caudal-fin base. Transverse rows of scales in front of dorsal-fin origin 10; scale rows around caudal peduncle 12. Cephalic squamation pattern G-type. Two frontal neuromasts behind upper lip, posterior in shallow groove. Cephalic sensory system at supraorbital level in divided shallow groove with one and three exposed neuromasts, in anterior and posterior portions, respectively (Fig. 3 d), whereas at supratemporal level with four exposed neuromasts in undivided, slightly curved, shallow groove. Preorbital canal in shallow groove with three exposed neuromasts; infraorbital level with series of about dozen small buttons at ventral and posterior margin of orbit; postorbital canal in deep groove with one exposed neuromast. Preopercular system with seven exposed neuromasts in deep groove. Mandibular canal in shallow groove with three small neuromasts. One neuromast on each scale along trunk mid-longitudinal series. Female: Slightly smaller than male, maximum recorded size 35.4 mm SL. Branchiostegal membrane not projecting posteriorly from opercle. Dorsal and caudal fins rounded, former with 15 – 17 rays. Anal fin subtriangular, tip rounded, central rays longer and more rigid. Anal fin positioned more posteriorly than in males (preanal length 61.7 – 67.1 % SL vs. 53.7 – 57.6), and base length smaller than in male (18.6 – 21.4 % SL vs. 23.4 – 26.7). Head width larger than in males (59 – 63 % HL vs. 54 – 59) whereas head depth smaller than in males (79 – 81 % HL vs. 83 – 87). Colouration. Live male (Figs. 6 A – C): Scales on trunk and head are iridescent blue to blue-green with narrow brown to red-brown margins, forming a regular reticulation pattern with, on the posterior part of the body, a weakly developed diagonally-barred or chevron pattern. Scales on abdomen light blue to white with less pronounced margins that are paler red-brown to yellow-brown in colour. Scales on the dorsum anterior to dorsal fin have broader margins and may have yellow-tinged centres. Snout, frontal and dorsal portions of the head are mainly brown although some populations show red lips; the throat is pale blue to blue-green with a yellow tinge. Operculum has light blue to blue-green scale centres with red-brown margins in the upper part, grading to yellow margins in the lower part. Exposed part of branchiostegal membrane is yellow to white. Iris is blue to blue-green. The dorsal fin background is iridescent yellow-brown to golden colour and, in some populations, may show a red tinge in the basal and proximal zones and some blue green colour in the distal zone. The background is overlaid by dark red-brown to maroon spots that are arranged in such a way as to coalesce in part, forming irregular concentric bands or, in some specimens, lines parallel to the fin rays; the latter linear arrangement is more prominent in the basal and proximal zones but may extend through the medial zone. A narrow dark red to maroon marginal band is invariably present and some specimens also show light blue tips to short fin-ray extensions. The anal fin background comprises a light blue to grey basal zone grading to blue-green, yellow-green or yellow in the remainder of the fin. The background is overlaid by 5 – 7 dark maroon bands, the most distal of which forms a marginal band. The innermost bands in the proximal and submedial zones may be relatively indistinct and short, where the others are distinct and prominent extending fully across the fin in a pattern ranging from straight to curved, more or less parallel to the distal margin. Background colour of the caudal fin is variable: it can be yellow in the basal, proximal and medial zones grading to a lighter yellow or blue in the subdistal zone; or blue-green or blue in the basal, proximal and medial zones, grading to blue in the subdistal zone; or blue or yellow throughout the basal to subdistal zones. The background is overlaid by 4 – 5 concentric bars conforming to the general outer shape of the fin comprising, essentially, rows of coalescent dark maroon spots. There is a distinct black marginal band most commonly preceded by a submarginal zone relatively free of maroon markings and which appears as a distinct band showing the background colour. Pelvic fins mimic, in a simpler fashion, the colour pattern of the anal fin with maroon markings, arranged in a crude banding, on a yellow, blue-green or blue background. Pectoral fins are dominantly hyaline with poorly developed, and usually only partial, blue margins. Live female (Fig. 6 D): Trunk and head light grey, darker on the dorsum and lighter ventrally. Scales on the flanks have narrow darker grey-brown margins which may form a faint reticulated pattern on the posterior part of the body; scale centres on the trunk above the abdomen are iridescent pale blue; the operculum is iridescent light blue or yellow. All fins hyaline. The iris is pale golden.	en	Watters, Brian R., Nagy, Béla (2025): A review and redefinition of the subgenus Aphyobranchius Wildekamp, 1977, in the seasonal killifish genus Nothobranchius Peters, 1868 (Teleostei: Nothobranchiidae), from ephemeral wetlands of eastern Tanzania. Zootaxa 5570 (3): 401-446, DOI: 10.11646/zootaxa.5570.3.1, URL: https://doi.org/10.11646/zootaxa.5570.3.1
03E187C8FF9DDD40FF1D850434623DBB.taxon	distribution	Distribution. Nothobranchius lourensi is endemic to seasonal freshwater habitats in coastal Tanzania and is the most widespread member of the Aphyobranchius subgenus, occurring most abundantly in the marginal and peripheral zones of the Kibasira Swamp in the Kilombero River valley but relatively sparsely elsewhere (Fig. 1). The Kilombero system represents a fairly remote component of the Rufiji River system, connected to it through the Ulanga River, the downstream continuation of the Kilombero River. Relatively rare, isolated, single site occurrences have also been reported from: the lower Ruvu River near Kwaraza, representing the type location; a couple of sites in the lower Rufiji River system, one associated with the Ruhoi River and another situated 2 km south of the main course of the Rufiji River near where it approaches the delta; a single occurrence is also known from the Luhule / Luhute River floodplain within the so-called Mbezi Triangle (sensu Watters et al. 2007; Watters 2009). Conservation status. Nothobranchius lourensi has been evaluated as Near Threatened (Nagy & Watters 2019 d). The known extent of occurrence (EOO) is 28,006 km ². Within its area of distribution, the occurrence of the species is currently known from more than 10 threat-based locations, with disjunct populations in several river drainages. There is increasing habitat degradation due primarily to expansion of agriculture in the area, including the conversion of some seasonal habitats into permanent ponds (e. g. in the Kwaraza area of the lower Ruvu River system, where the type locality occurs), thereby modifying them in ways that render them unsuitable to support the seasonal life cycle of the species.	en	Watters, Brian R., Nagy, Béla (2025): A review and redefinition of the subgenus Aphyobranchius Wildekamp, 1977, in the seasonal killifish genus Nothobranchius Peters, 1868 (Teleostei: Nothobranchiidae), from ephemeral wetlands of eastern Tanzania. Zootaxa 5570 (3): 401-446, DOI: 10.11646/zootaxa.5570.3.1, URL: https://doi.org/10.11646/zootaxa.5570.3.1
03E187C8FF99DD4DFF1D876034A6393F.taxon	description	(Figs. 7 A – B)	en	Watters, Brian R., Nagy, Béla (2025): A review and redefinition of the subgenus Aphyobranchius Wildekamp, 1977, in the seasonal killifish genus Nothobranchius Peters, 1868 (Teleostei: Nothobranchiidae), from ephemeral wetlands of eastern Tanzania. Zootaxa 5570 (3): 401-446, DOI: 10.11646/zootaxa.5570.3.1, URL: https://doi.org/10.11646/zootaxa.5570.3.1
03E187C8FF99DD4DFF1D876034A6393F.taxon	materials_examined	Material examined. RMCA 1997.082. P. 0032 - 0033, 1 male, 36.2 mm SL, 1 female, 24.2 mm SL; Tanzania: Rufiji drainage, Kitonga; 08 ° 03.13 ’ S, 39 ° 00.53 ’ E; B. Watters, R. Wildekamp, B. Cooper; 31 May 1997; field code: TAN 97 - 9. Additional material examined. 2 males, 35.1 – 43.4 mm SL, 1 female 25.9 mm SL; Tanzania: Rufiji drainage, Kitonga; 08 ° 03.13 ’ S, 39 ° 00.53 ’ E; B. Watters, R. Wildekamp, B. Cooper; 31 May 1997; field code: TAN 97 - 9.	en	Watters, Brian R., Nagy, Béla (2025): A review and redefinition of the subgenus Aphyobranchius Wildekamp, 1977, in the seasonal killifish genus Nothobranchius Peters, 1868 (Teleostei: Nothobranchiidae), from ephemeral wetlands of eastern Tanzania. Zootaxa 5570 (3): 401-446, DOI: 10.11646/zootaxa.5570.3.1, URL: https://doi.org/10.11646/zootaxa.5570.3.1
03E187C8FF99DD4DFF1D876034A6393F.taxon	diagnosis	Diagnosis. Nothobranchius fuscotaeniatus is here assigned to the N. lourensi species group of the subgenus Aphyobranchius by presenting the following combination of characters in males, compared to those of other subgenera: anal fin trapezoidal in shape with a concave lower margin (vs. rounded with convex lower margin); caudal fin rounded with 2 – 3 central rays slightly elongated forming a mild central lobe (vs. central lobe absent); spawning behaviour in mid-water levels (vs. spawning directly into the substrate), and molecular phylogenetic relationships. Nothobranchius fuscotaeniatus is further distinguished from all the other members of the genus Nothobranchius by the unique diagnostic characters of male colouration comprising a green-blue body with 10 – 12 distinct red-brown crossbars on entire trunk that extend into dorsal and anal fins; anal and dorsal fins green-blue with crossbars extending from trunk into the proximal and medial parts and with broad black distal band; caudal fin with slender yellow to yellow-green medial band and broad black distal band; as well as female colouration with a unique pattern of light blue and red-brown crossbars on the body and a light blue iridescence on the dorsal and anal fins.	en	Watters, Brian R., Nagy, Béla (2025): A review and redefinition of the subgenus Aphyobranchius Wildekamp, 1977, in the seasonal killifish genus Nothobranchius Peters, 1868 (Teleostei: Nothobranchiidae), from ephemeral wetlands of eastern Tanzania. Zootaxa 5570 (3): 401-446, DOI: 10.11646/zootaxa.5570.3.1, URL: https://doi.org/10.11646/zootaxa.5570.3.1
03E187C8FF99DD4DFF1D876034A6393F.taxon	description	Description. General body features illustrated by Figures 7 A – B. Morphometric and meristic characters of examined material are summarized in Table 7. Male: Medium-sized Nothobranchius species, maximum recorded size 43.4 mm SL. General body shape robust, laterally compressed and deep. Greatest body depth at vertical passing through pelvic-fin origin, 32.5 – 35.3 % SL. Greatest body width at pectoral-fin base with body progressively narrowing towards caudal-fin base. Dorsal profile convex from tip of snout to dorsal-fin origin, straight to slightly concave on caudal peduncle. Ventral profile convex from lower jaw to base of last anal-fin ray, straight to slightly concave on caudal peduncle. Caudal peduncle deep, length 146 – 153 % of its depth. Anus situated directly in front of anal-fin origin. Head moderately long (30.4 – 33.6 % SL), laterally compressed, deeper than wide (head width 64 – 69 % of its depth). Snout distinctly pointed, smaller than eye diameter. Mouth supraterminal, slightly oblique in profile. Jaws subequal, lower jaw longer than upper, posterior end of rictus at same level or slightly ventral to centre of eye. Premaxilla and dentary with many irregularly distributed conical teeth on inner rows and slightly curved teeth on outer row. Orbit large, eye diameter 33 – 36 % HL, positioned entirely in anterior half of head (snout to eye end length 47 – 50 % HL). Branchiostegal membrane projecting posteriorly from opercle. Dorsal-fin origin at same vertical positioning as anal-fin origin (mean predorsal length 100 – 101 in % of preanal length), both fins originating slightly posterior to mid-length of body (predorsal length 53.0 – 55.5 % SL; preanal length 52.3 – 55.5 % SL). Dorsal fin with 15 – 16 rays, extremity rounded. Anal fin trapezoidal in shape, with 17 – 18 rays; lower margin moderately concave in profile. Dorsal and anal fins with short fin-ray extensions. Pectoral fin subtriangular, insertion slightly posterior to margin of opercular opening, base slightly oblique, upper fin rays positioned slightly anterior to lower fin rays, with tip reaching or slightly overlapping base of pelvic fin. Pelvic fin subabdominal, origin at about mid-length of body, short, base medially separated, with tip reaching urogenital papilla. Caudal fin rounded, with 16 – 18 branched rays, plus 3 – 4 dorsal and ventral procurrent rays; central 2 – 3 rays of fin relatively slightly elongated resulting in mild central lobe. Scales cycloid, body and head entirely scaled, except for ventral surface of head. No scales on base of dorsal and anal fins. Scales in mid-longitudinal series 25 – 26 plus two or three small scales on caudal-fin base. Transverse rows of scales in front of dorsal-fin origin 10; scale rows around caudal peduncle 12. Cephalic squamation pattern G-type. Two frontal neuromasts behind upper lip, posterior in shallow groove. Cephalic sensory system at supraorbital level in divided shallow groove with one and three exposed neuromasts, in anterior and posterior portions, respectively (Fig. 3 d), whereas at supratemporal level with four exposed neuromasts in undivided, slightly curved shallow groove. Preorbital canal in shallow groove with three exposed neuromasts; infraorbital level with series of about dozen small buttons at ventral and posterior margin of orbit; postorbital canal in deep groove with one exposed neuromast. Preopercular system with seven exposed neuromasts in deep groove. Mandibular canal in shallow groove with three small neuromasts. One neuromast on each scale along trunk mid-longitudinal series. Female: Smaller than male, maximum recorded size 25.9 mm SL. Branchiostegal membrane not projecting posteriorly from opercle. Dorsal and caudal fins rounded. Anal fin subtriangular, tip rounded, central rays longer and more rigid. Dorsal fin positioned more posteriorly than in males (predorsal length 61.8 – 66.1 % SL vs 53.0 – 55.5). Anal fin positioned more posteriorly than in males (preanal length 62.2 – 66.9 % SL vs. 52.3 – 55.5), and base length smaller than in males (18.5 – 21.9 % SL vs. 24.3 – 26.7). Head width larger than in males (59 – 63 % HL vs. 55 – 58) whereas head depth smaller than in males (80 – 81 % HL vs. 85 – 86). Colouration. Live male (Fig. 7 A): The body has a series of as many as 12 prominent dark red-brown crossbars resulting from broad scale margins. Scales in the relatively wider intervening sections are a brilliant iridescent blue to blue-green with very narrow dark red-brown edgings. The snout is blue-green to yellow with irregular dark markings including some on the lips. The throat and operculum are yellow to blue-green. The exposed part of the branchiostegal membrane is yellow with black edging. Scales on the dorsum anterior to the dorsal fin may have medium brown centres forming a vague stripe between the dorsal fin and snout. The barred colour pattern of the trunk extends onto the abdomen with intervening scales grading into light green, with only vague dark edgings, that may extend posteriorly to the caudal fin base. The iris is blue-green. The dorsal fin background colour is blue-green in the basal and proximal zones grading to yellow-green through the medial zone; the background is overlaid by irregular dark red-brown to black spots and short crude bars that appear as extensions of the dark bars on the body, becoming broken up and smaller outwards; the distal zone comprises a black marginal band with very narrow light blue to blue-green edging. The anal fin is somewhat similar in colour pattern to the dorsal fin; the basal zone is blue grading to blue-green in the proximal zone through to yellow-green in the medial zone. The basal, proximal and submedial zones are overlaid by dark red-brown to black irregular markings that represent extensions of the dark bars on the body; these irregular markings usually do not extend into outer part of the medial zone but, when they do, they appear broken and sparse; the distal zone comprises a broad black marginal band with very narrow light blue to blue-green edging that is less well developed than in the dorsal fin and may only be present on the very short fin-ray extensions. The caudal fin displays a prominent concentrically-banded pattern; the basal zone is blue-green followed by a narrow arc-like dark red-brown to black band in the proximal zone, followed by a yellow-green band and another, broader, black band and then a yellow to yellow-green band; the distal zone comprises a broad black band. Pelvic fins are blue-green with a black marginal zone. Pectoral fins are hyaline with, in some specimens, very poorly developed and usually only partial, light blue margins. Live female (Fig. 7 B): The body has up to 10 narrow cross-bars formed by very dark red-brown or black scale margins. These are similar to those shown by the male but are less well defined in the female and more distinct anteriorly. Scales in the intervening parts of the body have iridescent light blue to blue-green centres and yellow-brown scale margins. Scales on the dorsum are yellow-brown. The head is yellow-brown with some irregular dark red-brown to black markings; the throat is pale yellow-brown. The lower part of the operculum is yellow and there is a patch immediately posterior to the operculum that has broad bright yellow scale margins. Scales on the abdomen are light yellow-brown, some showing iridescent light blue centres and bright yellow margins. The dorsal and anal fins have yellow-brown fin rays with the intervening membrane being iridescent blue-green; the distal component is grey; some dark spots are sparsely present over most of the fins and those at or near the fin bases show a crude extensional arrangement with the bars on the body. The caudal, pectoral and pelvic fins are hyaline. The iris is golden grading outwards to blue-green.	en	Watters, Brian R., Nagy, Béla (2025): A review and redefinition of the subgenus Aphyobranchius Wildekamp, 1977, in the seasonal killifish genus Nothobranchius Peters, 1868 (Teleostei: Nothobranchiidae), from ephemeral wetlands of eastern Tanzania. Zootaxa 5570 (3): 401-446, DOI: 10.11646/zootaxa.5570.3.1, URL: https://doi.org/10.11646/zootaxa.5570.3.1
03E187C8FF99DD4DFF1D876034A6393F.taxon	distribution	Distribution. Nothobranchius fuscotaeniatus is known from a single site only, comprising an originally thickly vegetated ditch on the immediate west side of a now defunct road, about 2 km southwards from the south bank terminus for the old ferry across the Rufiji River (Fig. 1). It is, therefore, within the lower Rufiji River drainage. Since the original discovery of this species by the first author and colleagues in May, 1997, and also soon after by Seegers (1997), numerous visits to that site have been unable to find it there again. Conservation status. Nothobranchius fuscotaeniatus is listed as Critically Endangered B 2 ab (iii) (Nagy & Watters 2019 e). The species is currently known only from the type locality with an area of occupancy (AOO) of 4 km 2. Several surveys in the years following the original discovery were unable to detect its presence at either the type locality or elsewhere in the drainage of the Rufiji River, whereas other congeners were found in abundance at the type locality and in the general area. As shown in Nagy & Watters (2021) and Figure 7 D herein, the type locality has been significantly modified since the species was first discovered in 1997. Extensive local farming around the type locality represents increasing pressure on land resources that has resulted in habitat degradation in the area. The species is adapted to specific habitat conditions by occupying a niche among the densely vegetated marginal zones of the pool and is likely, therefore, to be very highly susceptible to habitat modifications by agriculture, which invariably results in habitats becoming more open.	en	Watters, Brian R., Nagy, Béla (2025): A review and redefinition of the subgenus Aphyobranchius Wildekamp, 1977, in the seasonal killifish genus Nothobranchius Peters, 1868 (Teleostei: Nothobranchiidae), from ephemeral wetlands of eastern Tanzania. Zootaxa 5570 (3): 401-446, DOI: 10.11646/zootaxa.5570.3.1, URL: https://doi.org/10.11646/zootaxa.5570.3.1
